That's a great feature and gsprating.com/forum has something similar. Scroll to the bottom of any page and you'll see two drop downs. The one on the left is "New/Recently Updated Topics" which is exactly what your looking for.

Thats great if you want to see new posts and have the time to select each individual forum. But where I visit numerous forums daily I usually just click on the NEW POST link initially and it will list all topics for all forums rather than me having to use pull-down menus to accomplish what should be a 1 click task. Just my opinion.